In general, an imaging pickup device that can capture both still and moving pictures performs focusing and zooming by means of a focus actuator that drives a single focus lens group and a zoom actuator that drives a single zoom lens group. The focus actuator and the zoom actuator consist of a DC motor, a stepping motor, an ultrasonic motor, or the like. Focal position detection during moving picture capture is accomplished by performing what is known as wobbling, in which the focus lens group is moved back and forth over a tiny range in the optical axis direction. During zooming, the focus lens group performs wobbling around a zoom tracking curve to match the movement of the zoom lens group, and zoom tracking and focal position detection are carried out simultaneously.